( $their_sig_hex: expr, $our_sig_hex: expr, $tx_hex: expr) => {
unsigned_tx = chan.build_commitment_transaction(42, &keys, true, false).unwrap();
let their_signature = Signature::from_der(&secp_ctx, &hex_bytes($their_sig_hex).unwrap()[..]).unwrap();
( $their_sig_hex: expr, $our_sig_hex: expr, $tx_hex: expr) => {
unsigned_tx = chan.build_commitment_transaction(42, &keys, true, false).unwrap();
let their_signature = Signature::from_der(&secp_ctx, &hex_bytes($their_sig_hex).unwrap()[..]).unwrap();